Conservation and Population Status of Freshwater Fishes from Kelekar River, South Sumatra, Indonesia

: This study assessed the conservation and population status of the fish species collected from the Kelekar river. This study was conducted between May 2022 and June 2023. A total of 1.267 fish belonging to 49 species and 19 families were recorded. Cyprinidae was found to be the richest family (18 species) followed by Osphronemidae (5 species), Channidae (4 species), Siluridae (3 species), Bagridae, Claridae, Pangasidae, Pristolepidae (2 species), and others (1 species). The Shannon-Weiner diversity index was 3.547. The Simpson’s dominance index was 0.035, and the Evenness index was 0.921. The biodiversity index of the Kelekar river was in the high category. Base on the latest IUCN red list, one species as data deficient, forty-three species as least concern, two species as near threatened, two species as vulnerable, and one species as critically endangered. The IUCN based population status of fish species present in the Kelekar River was unknown (35%)


INTRODUCTION
Indonesia is the biggest archipelago country in the world.Stretching from Sabang to Merauke, Indonesia has 17.499 islands with a total area of approximately 7.81 million square kilometers.The area of the waters is about 75% of the total area.Its freshwater area (including rivers, reservoirs, and swamps) is 141.690 hectares.One of the rivers in Indonesia is the Kelekar river.The Kelekar River is located in Ogan Ilir Regency, South Sumatra Province.This river is used by local people for daily activities such as household activities, fishing, and also transportation.Some water quality parameters in the Kelekar River are temperature 25-32 o C, depth 60 -400 cm, dissolved oxygen 3.45-6.56mg.L -1 , ammonia 0.002-0.341mg.L -1 , and alkalinity 30-60 mg.L -1 (Muslim, 2020).The biodiversity index of Kelekar river was in the medium category.The diversity index was 2.183-2.691,evenness index was 0.764-0.871,and dominance index was 0.045 (Muslim and Syaifudin, 2021).The Kelekar River is a habitat for various types of fish.Fishes inhabiting rivers are severely affected due to reduced water flow, overfishing, and increased water pollution.The study of biological and ecological aspects of this river is very limited.Several studies have been conducted on parasites in clown loach fish (Robin, 2007), gonadal maturity of snakehead fish (Muslim, 2007), plankton community (Silaen et al., 2011), water quality (Muslim, 2019;Amalia, 2019), DNA coded for striped snakehead and ocellated snakehead fish (Syaifudin et al., 2020), fish diversity (Muslim and Syaifudin, 2021), and river flow characteristics (Fajari and Haki, 2022).Studies on the conservation and population status of fish in the Kelekar River have not been carried out.The purpose of this study was to evaluate the conservation and population status of fish caught in the Kelekar River.The results of this study are beneficial for the government and other stakeholders to design management strategies for aquatic resources in Ogan Ilir Regency.

MATERIAL AND METHOD
A total of three sampling stations on Kelekar River were selected for the present study.1).Sampling occurred over the period May 2022 to June 2023.Fishes were caught with traditional fishing gears such as empang (fish barrier), arat waring (seine net), jaring angkat (lift net), jaring insang (gill net).A digital camera was used to capture photos of different fish species.The collected fish samples were identified by their morphometric and meristic (https://www.iucnredlist.org/).The valid scientific and common names of the identified fish species were ensured by checking the database of the fish (https://www.fishbase.se/).Where S is the number of species in the sample, and Pi is the relative importance values obtained as the squared ratio of the important values of S individual value for all species to N the total importance.
Determination of criteria: H' < 1.0 (low), H' = 1.0 -3.0 (medium), and H' > 3.0 (high) The evenness index was calculated by a formula Magurran (1988): Where, H' is Shannon-Wiener diversity index, E is evenness index (value 0-1), and H' max is maximum diversity index.Determination of criteria: E < 0.4 (low), E = 0.4-0.6 (medium), and E > 0.6 (high) The dominant fish species was determined using the following formula (Davari et  Where, C is Simpson's dominance index, is the relative importance values obtained as the squared ratio of the important value, is the individual value for all species.

RESULT AND DISCUSSION
A total of forty-nine species under nineteen families were collected from the three sampling stations.Among the recorded species, eighteen species of fishes were represented from the Cyprinidae family, five from Osphronemidae, four from Channidae, three from Siluridae, two species each belonged to Bagridae, Claridae, Pangasidae, Pristolepidae, and one each representative species from Ambassidae, Anabantidae, Aplocheilidae, Datnioididae, Helostomatidae, Eleotridae, Mastocembelidae, Nandidae, Notopteridae, Synbranchidae, and Tetraodontidae are depicted in Base on the latest IUCN red list, one species (2%) as data deficient, forty-three species (88%) as least concern, two species (4%) as near threatened, two species (4%) as vulnerable, and one species (2%) as critically endangered (Figure 3).The population trend of fishes in the Kelekar river was unknown (35%), stable (47%), and decreasing (18%) (Figure 4).A list of existing fish species with their family name, species, conservation and population status, and last assessed are presented in Table 1 and Tabel 2.   This study shows that there are various types of fish in the Kelekar river.A total of 1.267 identified individuals can be classified into 19 families, 36 genera, and 49 species.The Cyprinidae consists of 14 genera, Osphronemidae (3), each Siluridae and Bagridae (2), and others (1).The Cyprinidae consists of 18 species, Osphronemidae (5), Channidae (4), Siluridae (3), Claridae, Bagridae, Pangasidae, Pristolepidae (2), and others (1).Five hundred four (504) individuals were dominated by members of the Cyprinidae, followed by the Osphronemidae (151), Channidae (120), Pristolepidae (109), Anabantidae (79), Helostomatidae (68), Ambassidae (48), Siluridae (44), Bagridae (39), Claridae (28), Pangasidae (18), Notopteridae (13), Eleotridae (11), Synbranchidae (9), Nandidae (8), Tetraodontidae (5), Aplocheilidae (5), Mastocembelidae (4), and Datnioididae (3).The Shannon-Weiner diversity index was 3.532.The Simpson's dominance index was 0.036, and the Evenness index was 0.917 (Table 3).The biodiversity index of the Kelekar River was in the high category.Fish are a richly diverse group of chordates, with more than 33,500 species, more than all non-fish vertebrates combined.Freshwater fish comprise over 16,000 species distributed worldwide (Miranda and Miqueleiz, 2021).They are also one of the most endangered groups of vertebrates, particularly vulnerable to human alterations such as species introduction, overexploitation, population declines, degradation of continental waterways, and climate change.However, knowledge of the ecology and conservation status of freshwater fishes is lower than that of terrestrial groups due to a bias in conservation research towards charismatic species.The diversity of freshwater fish has been severely threatened by human activities in recent decades, making the conservation of freshwater fish and their ecosystems an urgent priority (Cao et al., 2023).The conservation of fish and their habitats has received very little attention compared to other vertebrates (Maitland, 1995).More than 1.2 million species have been described as existing on Earth, and many more are still unidentified (Mora et al., 2011).

CONCLUSIONS
In the present study, forty-nine species of fish were recorded.The biodiversity index of the Kelekar river was in the high category.
As per the recent IUCN Red List, the conservation status of the fishes showed one species critically endangered, two species vulnerable, two species near threatened, forty-three species least concern, and one species data deficient.The population trend of fish was unknown (35%), stable (47%), and decreasing (18%).
keys ofKottelat et al., (1993) andSaanin (1984).The global conservation, population trend, and last assessment were determined following the database of the IUCN Red List of threatened species.version 2022-1.

Figure 1 :
Figure 1: Map of sampling site in the Kelekar river, Ogan Ilir Regency, Indonesia

Figure 2 .
Priono et al. (2001); Muslim and Syaifudin (2021) reported that the Cyprinidae family was part of the major fish composition in the Kelekar River.A similar trend was observed in the present findings.

Figure 5 :
Figure 5: Eleven dominant species found in the Kelekar River, Ogan Ilir Regency, Indonesia

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According to De Vos et al., (2015), the rate of extinction of species is 1000 times quicker than it was in the fossil record, and the sixth mass extinction (Ceballos et al., 2017) is one of the most significant problems of the 21st century.The primary drivers of the excessive biodiversity loss in ecosystems are human-caused factors such species invasions, habitat modification, and climate change Dudgeon et al., 2006; Dirzo et al., 2014; Reid et al., 2019).Inland waters are among the most impacted ecosystems (Strayer and Dudgeon, 2010; Collen et al., 2014).

Table 1 : IUCN red list status of fishes caught in Kelekar River, Ogan Ilir Regency, Indonesia
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Table 2 : Population status of fishes caught in Kelekar River, Ogan Ilir Regency, Indonesia
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